NATS 1730 Lecture Notes - Lecture 11: Eosinophil, Atopy, Thyroiditis
17 Dec 2016
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Document Summary
Allergic and other hypersensitivity disorders are exaggerated or inappropriate immune reactions. The gell and coombs classification delineates 4 types of hypersensitivity reaction. Hypersensitivity disorders often involve more than 1 type. Type i: type i reactions (immediate hypersensitivity) are ige-mediated. Antigen binds to ige (which is bound to tissue mast cells and blood basophils), triggering release of preformed mediators (eg, histamine, proteases, chemotactic factors) and synthesis of other mediators (eg, prostaglandins, leukotrienes, platelet-activating factor, cytokines). These mediators cause vasodilation, increased capillary permeability, mucus hypersecretion, smooth muscle spasm, and tissue infiltration with eosinophils, type 2 helper t cells (th2), and other inflammatory cells. Type i reactions underlie atopic disorders (eg, allergic asthma, rhinitis, conjunctivitis) and latex and some food allergies. Type ii: type ii reactions result when antibody binds to cellular or tissue antigens or to a molecule coupled to a cell or tissue.
